Optical signal amplifying triode and optical signal transfer method, optical signal relay device, and optical signal storage device using the same

Abstract

When in an optical signal amplifying triode 10 , light of a second wavelength λ 2 , selected from among light from a first optical amplifier 26 , into which a first input light L 1 of a first wavelength λ 1 and a second input light L 2 of second wavelength λ 2 have been input, and a third input light (control light) L 3 of a third wavelength λ 3 are input into a second optical amplifier 34 , an output light L 4 of the third wavelength λ 3 , selected from among the light output from the second optical amplifier 34 , is light that is modulated in response to the intensity variation of one or both of the first input light L 1 of the first wavelength λ 1 and the third input light L 3 of the third wavelength λ 3 and is an amplified signal, with which the signal gain with respect to the third input light (control light) L 3 of the third wavelength λ 3 is of a magnitude of 2 or more. An optical signal amplifying triode 10 , which can directly perform an optical signal amplification process using control input light, can thus be provided.

1. An optical signal transfer method of transferring an optical signal train, which has been transmitted via a predetermined transmission path, to transmission paths, among a plurality of transmission paths, that correspond to routing information contained in the optical signal, the optical signal transfer method comprising:
 an input step of inputting the optical signal train, to which the routing information have been applied, to the main optical signal amplifying triode unit; 
 a wavelength conversion step of supplying control light of wavelengths, corresponding to signals indicating the routing information, to the main optical signal amplifying triode unit, and making optical signals of the wavelengths of the control light be output from the main optical signal amplifying triode unit; and 
 an optical distribution step of inputting the optical signals, output from the main optical signal amplifying triode unit, into an optical distributor and distributing the optical signals according to their wavelengths among the plurality of optical transmission paths connected to the optical distributor. 
 
   
   
     2. The optical signal transfer method according to  claim 1 , wherein in the wavelength conversion step, amplitude modulation using the control light is applied to the optical signals, output from the main optical signal amplifying triode unit, to add new routing information to the optical signals. 
   
   
     3. The optical signal transfer method according to  claim 1 , wherein the optical signal train is amplitude modulated at a modulation degree of no more than 90%. 
   
   
     4. An optical signal relay device, which, among optical signal transmission networks, transfers an optical signal train, having routing information added thereto by amplitude modulation, from one network to transmission paths, among the transmission paths of another network, that correspond to the routing information contained in the optical signal, comprising:
 a control light generator, generating, based on the amplitude modulation signals of the optical signal train, control light of wavelengths corresponding to the destinations indicated by the amplitude modulation signals; 
 a main optical signal amplifying triode unit, converting the optical signal train into an optical signal of the wavelengths of the control light; and 
 an optical distributor, distributing the optical signal, output from the main optical signal amplifying triode unit, among a plurality of optical transmission paths in accordance with the wavelengths of the optical signal. 
 
   
   
     5. The optical signal relay device according to  claim 4 , further comprising an electronic controller or an all-optical controller, which, in accordance with the amplitude modulation signals contained in the optical signal, makes control light of wavelengths, which are in accordance with the routing information indicated by the amplitude modulation signals, be generated from the control light generator. 
   
   
     6. The optical signal relay device according to  claim 5 , further comprising:
 an optical splitter, branching a portion of the optical signal; 
 a photoelectrical signal converter, converting the optical signal branched by the optical splitter to an electrical signal and supplying the electrical signal to the electronic controller; and 
 an optical delay element, disposed at the downstream side of the optical splitter and delaying the optical signal that is to be input into the main optical signal amplifying triode unit upon passage through optical splitter; and 
 wherein the electronic controller extracts the amplitude modulation signals contained in the optical signal and makes control light of wavelengths, which are in accordance with the routing information indicated by the amplitude modulation signals, be generated from the control light generator. 
 
   
   
     7. The optical signal relay device according to  claim 5 , further comprising:
 an optical signal storage element, temporarily storing an optical distributed from the optical signal distributor; and an optical feedback transmission path, feeding back the optical signal output from the optical signal storage element to the input side; and wherein 
 when the optical signal is an optical packet signal that is to be stored temporarily, the electronic controller makes a control optical signal, for converting the optical packet signal to a priorly set storage wavelength, be output, and 
 the optical distributor distributes the optical packet signal, after conversion to the storage wavelength, to the optical signal storage element and makes the optical packet signal be stored temporarily in the optical signal storage element. 
 
   
   
     8. The optical signal relay device according to  claim 7 , wherein the optical signal storage element is equipped with a plurality of optical fibers, which are disposed in parallel and differ in optical propagation length in order to receive optical signals distributed by the optical distribution device,
 the electronic controller makes a control optical signal, for converting the optical packet signal to be stored temporarily to a priorly set storage wavelength in accordance with the storage time required of the optical packet signal, be output, and 
 the optical distributor distributes the optical packet signal, after conversion to the storage wavelength, to an optical fiber among the plurality of optical fibers of the optical signal storage element and temporarily stores the optical packet signal in the optical fiber. 
 
   
   
     9. The optical signal relay device according to  claim 5 , wherein the all-optical controller comprises: an optical coupler, branching a portion of the first input light; a continuous light source, generating continuous light of the same wavelengths as the control light; an optical coupler, multiplexing the continuous light from the continuous light source with the portion of the first input light from the optical coupler; and a semiconductor optical amplifier, receiving the light from the optical coupler, outputting control light having the modulation signals contained in the first input light, and being of slower response speed than the semiconductor optical amplifier. 
   
   
     10. The optical signal relay device according to,  claim 4 , wherein when output light that are from the main optical signal amplifying triode unit are input, the optical distributor selectively distributes the output light, which have been input, to optical transmission paths, among the plurality of optical transmission paths, that correspond to the wavelengths of the control light. 
   
   
     11. The optical signal relay device according to  claim 4 , wherein the optical distributor is an array waveguide grating type splitter, which comprises: a first slab waveguide, connected to an input port; a second slab waveguide, connected to a plurality of output ports; and a plurality of array waveguides, disposed between the first slab waveguide and the second slab waveguide and differing in length; and distributes input light that has been input into the input port among the plurality of output ports according to the wavelengths of the input light.